Calculation apparatus and method for calculating relationship between charge amount and potential

Abstract

According to one embodiment, a calculation apparatus includes a calculator. The calculator calculates a relationship between a charge amount and a potential according to an arbitrary initial charge amount based on a relationship between a charge amount and a potential of an electrode of a secondary battery on a charge side and a relationship between a charge amount and a potential of the electrode on a discharge side.

The invention claimed is: 
     
       1. A calculation apparatus comprising:
 a memory configured to store first relationships between charge amounts and open-circuit potentials of a cathode and anode of a secondary battery on a charge side and second relationships between charge amounts and open-circuit potentials of the cathode and anode on a discharge side; and 
 a first calculator configured to calculate relationships between charge amounts and open-circuit potentials of the cathode and anode according to arbitrary initial charge amounts of the cathode and anode based on the first relationships and the second relationships stored in the memory. 
 
     
     
       2. The apparatus according to  claim 1 , wherein the relationships between the charge amounts and the open-circuit potentials of the cathode and anode according to the arbitrary initial charge amounts of the cathode and anode include second relationships between charge amounts and open-circuit potentials of cathode and anode for charging from zero charge amounts, and third relationships between charge amounts and open-circuit potentials of the cathode and anode for discharging from full charge amounts. 
     
     
       3. The apparatus according to  claim 2 , wherein the relationships between the charge amounts and the open-circuit potentials of the cathode and anode according to the arbitrary initial charge amounts of the cathode and anode represent a first curve, the second relationships represent a second curve, and the third relationships represent a third curve, the first curve being between the second curve and the third curve. 
     
     
       4. The apparatus according to  claim 3 , wherein, for each of the cathode and anode, a voltage of a charge amount on the first curve is given by a ratio of a voltage of a charge amount on the second curve to a voltage of a charge amount on the third curve. 
     
     
       5. The apparatus according to  claim 1 , further comprising a third calculator to calculate a capacity of the secondary battery based on active material amounts of the cathode and anode and the relationships between the charge amounts and the open-circuit potentials of the cathode and anode. 
     
     
       6. A method executed by an information processing apparatus, the method comprising:
 storing in memory first relationships between charge amounts and open-circuit potentials of a cathode and anode of a secondary battery on a charge side and second relationships between charge amounts and open-circuit potentials of the cathode and anode on a discharge side; and 
 calculating relationships between charge amounts and open-circuit potentials of the cathode and anode according to arbitrary initial charge amounts of the cathode and anode based on the first relationships and the second relationships stored in the memory. 
 
     
     
       7. A calculation apparatus comprising:
 a memory to store first relationships between charge amounts and open-circuit potentials of a cathode and anode of a secondary battery; 
 a second calculator to perform regression analysis by using the first relationships, a measurement time, a terminal voltage value of the secondary battery determined by a current value of the secondary battery, and time variation of the terminal voltage value and the current value of the secondary battery during the measurement time to calculate active material masses and initial charge amounts of the cathode and anode, and an internal resistance value of the secondary battery, the first relationships being determined for each active material included in the cathode and anode; and 
 a first calculator to calculate relationships between charge amounts and open-circuit potentials of the cathode and anode according to arbitrary initial charge amounts of the cathode and anode by performing regression analysis based on the active material mass and the initial charge amounts. 
 
     
     
       8. The apparatus according to  claim 7 , the first relationships include second relationships between charge amounts and open-circuit potentials of the cathode and anode for charging from zero charge amounts, and third relationships between charge amounts and open-circuit potentials of the cathode and anode for discharging from full charge amounts. 
     
     
       9. The apparatus according to  claim 8 , wherein the first relationships represent a first curve, the second relationships represent a second curve, and the third relationships represent a third curve, the first curve being between the second curve and the third curve. 
     
     
       10. The apparatus according to  claim 9 , wherein, for each of the cathode and anode, a voltage of a charge amount on the first curve is given by a ratio of a voltage of a charge amount on the second curve to a voltage of a charge amount on the third curve. 
     
     
       11. The apparatus according to  claim 7 , further comprising a third calculator configured to calculate a capacity of the secondary battery based on active material amounts of the cathode and anode and the relationships between the charge amounts and the open-circuit potentials of the cathode and anode. 
     
     
       12. A method executed by an information processing apparatus, the method comprising:
 storing in memory first relationships between charge amounts and open-circuit potentials of a cathode and anode of a secondary battery; 
 performing regression analysis by using the first relationships, a measurement time, a terminal voltage value of the secondary battery determined by a current value of the secondary battery, and time variation of the terminal voltage value and the current value of the secondary battery during the measurement time to calculate active material masses and initial charge amounts of the cathode and anode, an active material mass and an initial charge amount of the cathode, and an internal resistance value of the secondary battery, the first relationships being determined for each active material included in the cathode and anode; and 
 calculating relationships between charge amounts and open-circuit potentials of the cathode and anode according to arbitrary initial charge amounts of the cathode and anode by performing regression analysis based on the active material mass and the initial charge amounts. 
 
     
     
       13. A non-transitory computer readable medium storing a computer program which is executed by a computer to provide the steps of:
 storing in memory first relationships between charge amounts and open-circuit potentials of a cathode and anode of a secondary battery on a charge side and second relationships between charge amounts and open-circuit potentials of the cathode and anode on a discharge side; and 
 calculating relationships between charge amounts and open-circuit potentials of the cathode and anode according to arbitrary initial charge amounts of the cathode and anode based on the first relationships and the second relationships stored in the memory. 
 
     
     
       14. A non-transitory computer readable medium storing a computer program which is executed by a computer to provide the steps of:
 storing in memory first relationships between charge amounts and open-circuit potentials of a cathode and anode of a secondary battery; 
 performing regression analysis by using the first relationships, a measurement time, a terminal voltage value of the secondary battery determined by a current value of the secondary battery, and time variation of the terminal voltage value and the current value of the secondary battery during the measurement time to calculate active material masses and initial charge amounts of the cathode and anode, an active material mass and an initial charge amount of the cathode, and an internal resistance value of the secondary battery, the first relationships being determined for each active material included in the cathode and anode; and 
 calculating relationships between charge amounts and open-circuit potentials of the cathode and anode according to arbitrary initial charge amounts of the cathode and anode by performing regression analysis based on the active material mass and the initial charge amounts.